Model based optimal management of a hybrid propulsion system for leisure boats

The strict emission standards for port approach and coastal navigation, and the fuel-saving requirements, in the marine sector, are pushing the manufactures to consider more advanced and alternative propulsion systems. In this context, this study deals with the design and management of an innovative hybrid thermal-electric propulsion system. The evaluations are referred to the case study of a leisure boat, which is used for passenger transportation in tourist areas. Experimental tests are carried out on single components, with a particular focus on re-calibration of the thermal engine, for its homologation and optimal use in the proposed hybrid architecture. The identification of proper management strategies is performed on the basis of a boat simulation model, which is set up starting from experimental data and characteristics of components. In this regard, an optimization procedure, based on the use of genetic algorithms, is performed in order to set the parameters of onboard energy management strategies and pursue the double objective of extending battery pack cycling life and reducing exhaust emissions. The obtained simulation results highlight the benefits of the proposed architecture showing sensible improvements in comparison with a traditional ICE based configuration. The methodology proposed in this paper enables reliable evaluations and preliminary optimization of energy management strategies, with a drastic reduction in experimentation time and general costs.